1. Field of the Invention
This invention relates to guides for cutting coving to form mitre joints, and a method of cutting coving to form a mitre joint.
2. Prior Art
Coving is used to cover the junction between the top of a wall of a building and the ceiling, and accordingly generally has two rear surface portions extending at right angles to one another. When the coving is in position, one of these surfaces is in contact with the wall and the other is in contact with the ceiling. Usually these two rear surfaces are joined by an intermediate rear surface inclined at 45 degrees to each of them. The major part of the front surface of the coving is normally curved, but there are two narrow strips, one of which in use is adjacent to the ceiling and extends parallel to the wall, while the other in use is adjacent to the wall and extends parallel to the ceiling.
When it is required to join two pieces of coving at an internal or external corner of a room, it is necessary to form a mitre joint. The plane of the most convenient mitre cut, required on each piece of coving, lies in a plane perpendicular to the ceiling and extending at 45 degrees to each wall. More accurately, in the case of an external joint, the plane of the cut extends at 135 degrees to each wall.
The required mitre cut can be made with the aid of a normal mitre box. However, in order to hold the saw blade at the correct angle with respect to the coving to provide the required cut, it is necessary for one of the two mutually perpendicular rear surfaces to be in contact with, or parallel to, the sides of the box and for the other such surface to be in contact with, or parallel to, the base of the box. This can be accomplished without too much difficulty if the coving fits within the mitre box. However the dimensions are normally such that the coving cannot be held conveniently within the box. Furthermore, since the intermediate rear surface joining the said two mutually perpendicular rear surfaces usually constitutes the major part of the rear of the coving, it would be more convenient to use this surface as the contact surface rather than either of the two mutually perpendicular surfaces which are usually relatively small.